It is CCCXXV.
325 is an integer and so there is no sensible way of representing it as a mixed number.
200 + 325 = 525
325 + 345 = 670
600 + 325 = 925
325 + 50 = 375
325% = [(3.25)/(1)] x 100
They both add up to 325
325
325 + 634 - 547 = 412
325% = 3.25 = 3 25/100 = 3 1/4
110 to 120 psi